I actually use all three...
I've got a few one tile areas, two tile areas, and three tile areas. All depends where the path is going and what the path looks like!
I usually pick single-tile paths that can be lined up to be two tiles wide in certain spots (like near bridges). I'm too lazy to have paths with different tiles for borders and stuff.
I don't have any QR paths. I unintentionally made some natural dirt paths, and I like how they look, so I'm just going to go with the natural dirt path
I use one tile in some areas, then 2 and 3+ wide on the other. Whatever I think that looks nice. I try to mix them up so it doesn't look like they're too wide xD
2-3 wide, there are parts where I use single wide paths but the majority of my town is 2 wide, and 3 wide by buildings. I like having varied paths, and I think that the 2 wide paths look the best and are easiest to traverse as the 1 wide are a bit skinny.
3 tiles wide, 2 in places like in front of bridges or weirdly placed houses. I like to run and i'm clumsy, so 3 tiles width works well for me. And i'm aiming for a modern city look, so the less uncovered grass there is, the better.